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K: Fachverband Kurzzeitphysik

K 5: Laser-Materie-Wechselwirkung und Laseranwendungen II

K 5.7: Vortrag

Dienstag, 18. März 2014, 15:30–15:45, SPA SR203

Boosting lifetime and optical emission of laser-induced plasma by electric discharge sparks — •Simon Eschlböck-Fuchs, Philipp Johann Kolmhofer, Marius Aurel Bodea, Josef Gerald Hechenberger, Norbert Huber, Johannes Heitz, and Johannes Pedarnig — Christian Doppler Laboratory for Laser-Assisted Diagnostics, Institute of Applied Physics, Johannes Kepler University Linz, A-4040 Linz, Austria

Laser-induced breakdown spectroscopy (LIBS) is a sensitive analytical measurement technique with limits of detection (LOD) in the range 1-30 ppm for many chemical elements depending on the matrix. Different techniques have been tried to enhance the optical emission of laser-induced plasma and to improve the sensitivity of the LIBS method. The techniques include double-pulse excitation, radiofrequency and microwave plasma, and high voltage discharge sparks. We report on the combination of LIBS with low-voltage high-current discharge sparks and the investigation of the properties of combined plasma. The spark between two metal electrodes is triggered by the laser-induced plasma on the sample surface. Time-resolved photography reveals very long lifetimes for the combined plasma (up to several milliseconds) and an increased plasma volume. LIBS spectra of combined plasma in general show emission lines of higher intensity than the spectra of conventional LIBS plasma.